title: Spin transition in a four-coordinate iron oxide.
abstract: Spin transition has attracted the interest of researchers in various fields since the early 1930s, with thousands of examples now recognized, including those in minerals and biomolecules. However, so far the metal centres in which it has been found to occur are almost always octahedral six-coordinate 3d(4) to 3d(7) metals, such as Fe(II). A five-coordinate centre is only rarely seen. Here we report that under pressure SrFe(II)O(2), which features a four-fold square-planar coordination, exhibits a transition from high spin (S = 2) to intermediate spin (S = 1). This is accompanied by a transition from an antiferromagnetic insulating state to a ferromagnetic so-called half-metallic state: only half of the spin-down (d(xz),d(yz)) states are filled. These results highlight the square-planar coordinated iron oxides as a new class of magnetic and electric materials.
authors.affiliation: Institute of Quantum Science, Nihon University, Chiyoda, Tokyo 101-8308, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kawakami
authors.forename: Y
authors.initials: Y
authors.lastname: Tsujimoto
authors.forename: H
authors.initials: H
authors.lastname: Kageyama
authors.forename: Xing-Qiu
authors.initials: XQ
authors.lastname: Chen
authors.forename: C L
authors.initials: CL
authors.lastname: Fu
authors.forename: C
authors.initials: C
authors.lastname: Tassel
authors.forename: A
authors.initials: A
authors.lastname: Kitada
authors.forename: S
authors.initials: S
authors.lastname: Suto
authors.forename: K
authors.initials: K
authors.lastname: Hirama
authors.forename: Y
authors.initials: Y
authors.lastname: Sekiya
authors.forename: Y
authors.initials: Y
authors.lastname: Makino
authors.forename: T
authors.initials: T
authors.lastname: Okada
authors.forename: T
authors.initials: T
authors.lastname: Yagi
authors.forename: N
authors.initials: N
authors.lastname: Hayashi
authors.forename: K
authors.initials: K
authors.lastname: Yoshimura
authors.forename: S
authors.initials: S
authors.lastname: Nasu
authors.forename: R
authors.initials: R
authors.lastname: Podloucky
authors.forename: M
authors.initials: M
authors.lastname: Takano
mesh_terms: D017097:Electric Impedance; D004583:Electrons; D005290:Ferric Compounds / Q000737:chemistry*; D008280:Magnetics; D011312:Pressure; D015204:Spectroscopy, Mossbauer; D013324:Strontium / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D013324:Strontium